Synchronous drive belt

Abstract

A synchronous drive belt for use in low speed and high torque applications has a zero pressure angle over a relatively greater portion of the fore and aft flank surfaces of the belt teeth when used in a belt-pulley combination. A pulley is also described which is particularly suitable for use in combination with the belt.

What is claimed is: 
     
       1. An endless synchronous drive belt comprised of a resilient elastomer, reinforced with one or more reinforcing members extending along and thereby defining a pitch line, with a succession of identical teeth, each having a tooth depth, uniformly spaced apart by their pitch P, having fore and aft flank surfaces, the space between adjacent teeth defining a land line and a tooth root radius which inscribes a 90° arc which forms the transition between the land line and a tangent to the flank surface perpendicular to the land line and has its center in said land area wherein each said flank surface is shaped in cross-section as an arc of a circle with a radius R having its center located in said land area no further than said centerline away from its opposed flank and below said land line from a distance equal to said tooth root radius up to one half said tooth depth. 
     
     
       2. The belt according to claim 1 wherein the tooth depth is between 30% and 60% of tooth pitch P. 
     
     
       3. The belt according to claim 1 wherein the tooth width W, being the widest distance between the fore and aft flank surfaces, is between 50% and 80% of tooth pitch P.